B&H is the best, no question. The largest photo store in the world. Adorama is second best in the US. Beach, Penn Camera, Calumet, also good. Badger Graphic is great for large format -- better than B&H for that -- and they probably sell DSLRs, too. Robert White in the UK is good.
FWIW, I was a photographer in my pre-kids life. I wouldn't want to guess at how much I spent on photography stuff over time, but certainly most of my money went to B&H. Excellent prices, excellent customer service.
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